Method for reducing complex frequency down-conversion impairments

1. An improved receiver comprising: a voltage controlled amplifier for adjusting the gain of a first input signal, a comparator and integrator for controlling said voltage controlled amplifier connected to the output of the voltage controlled amplifier and connected to a second input signal, a cross-correlator connected to the output of said voltage controlled amplifier and said second input signal, a first auto correlator connected to the output of said voltage controlled amplifier, a second auto correlator connected to said second input signal, a first mixer connected to said cross-correlator and the output of said voltage controlled amplifier for providing a correction signal to the signal output by said second auto correlator, and a second mixer connected to said cross-correlator and said second input signal for providing a correction signal to the signal output by said first auto correlator.

2. A method for improving image rejection by a receiver of a received signal s(t) of the form s(t) i(t)cos( 0 t) q(t)sin( 0 t), comprising: estimating a cross-correlation of an imaginary and real input signals, estimating an auto-correlations of the imaginary and real input signals, and reconstructing said imaginary and real input signals using said estimated cross-correlation and auto-correlations in accordance with i(t) 2i(t) q(t) and q(t) 2q(t) i(t) where: phase angle i(t) i signal (t) i image (t) i signal (t) A(t)cos( IF t (t)) i image (t) (t)cos( IF t (t)) IF 0 t q(t) q signal (t) q image (t) q signal (t) A(t)cos( IF t (t) ) q image (t) (t)sin( IF t (t)) arbitrary phase arbitrary phase phase angle of signal phase angle of signal A amplitude of signal IF intermediate frequency 0 frequency at time zero t frequency at time t.